This is a revised application with the goal of evaluating how a low level of response (LR) to alcohol relates to other domains in a person's life (e.g., drinking among peers, ways of coping with stress, etc.) to increase the risks for heavy drinking and alcohol-related problems in teenagers and young adults. The evaluations focus on an LR-Social Information Processing Model which is studied in the second generation from 437 families that represent a 97% follow-up of eligible pedigrees over a 20-year period. We propose to test the model during the 25-year follow-up when the offspring, the major focus of this work, will be relatively young. Data will be gathered directly from sons and daughters age 12 and above, as well as from the parents. The major analyses will test the full model on an estimated 250 drinkers from among the 327 offspring age 12-24. At the core of the model are the family history of alcoholism and the low LR to alcohol. We hypothesize that a low LR might alter a person's expectations of the effects of alcohol which then enhances the probability of using alcohol to cope with stress. The initial need for higher amounts of alcohol for effects might also enhance the probability of acquiring heavy-drinking friends, who then increase the likelihood of alcohol problems. The family history of alcoholism is projected to be associated with a child's observing heavy drinking in the home, which also affects the selection of heavy-drinking friends and problematical coping mechanisms. The revised application expands the background information on the self-report measure of the level of response to alcohol, presents specific power calculations relevant to the structural equation modeling approach being used, and demonstrates how age, gender, ethnic background, and the non-independence of ratings among siblings can be modeled within the analyses to enhance understanding of how a low LR operates in teenagers and young adults. Our ultimate goal is to identify ways to prevent the escalation of drinking and associated problems in young populations.